Blender inserts keyframes on multiple channels but I want it on one
In order to set a keyframe on an individual channel, simply right-click the property and right-click and select 'Insert Single Keyframe'.

Alternatively, you can click on the Animate Property 'dot' alongside the property in the right-hand properties panel :

In the Dope Sheet, you can move individual channel keyframes by simply selecting the keyframe for that specific channel only - and move it independently of any other channel(s).